Field of the Invention
The present invention relates to a zoom lens and an image pickup apparatus suitable an image pickup optical system, for example, such as a digital camera, a video camera, a TV camera, a security camera, and a silver-halide film camera.
Description of the Related Art
A wide angle of view, a small size in an entire lens system and an image stabilizing mechanism are demanded for a zoom lens used for an image pickup apparatus. Especially, in the case of correcting an image blurring by moving an image stabilizing lens unit in a direction perpendicular to an optical axis direction, a small and light image stabilizing lens unit and a low variation in aberrations when correcting the image blurring are demanded so as to miniaturize a moving mechanism (an image stabilization mechanism) and save electric power thereof.
Therefore, it is important for a zoom lens having an image stabilizing mechanism to properly set configurations of an entire lens system and an image stabilizing lens unit. For example, it is important to properly set a refractive power of the image stabilizing lens unit and a distance between an aperture stop and the image stabilizing lens unit. If these configurations are not properly set, it is difficult to achieve a miniaturization in an entire system, a wide angle of view and a miniaturization of an image stabilizing mechanism and maintain a high optical performance during vibration control.
A negative-lead type zoom lens arranging a lens unit having a negative refractive power on the most object side is suitable for acquiring a zoom lens having a wide angle of view.
U.S. Pat. No. 7,382,550 discloses a fourth group zoom lens having, in order form an object side to an image side, a first, a second, a third and a fourth lens unit respectively having a negative, a positive, a negative and a positive refractive power and moving a part of the second lens unit in a direction perpendicular to an optical axis so as to correct an image blurring.
U.S. Pat. No. 8,189,074 discloses a fifth group zoom lens having, in order form an object side to an image side, a first, a second, a third, a fourth and a fifth lens unit respectively having a negative, a positive, a positive, a negative and a positive refractive power and moving the fourth lens unit in a direction perpendicular to an optical axis so as to correct an image blurring.